Sarcoma cells sialic acid

The repulsive, electrostatic forces of sialic acids contribute to the rigidity of the cell surface, as was shown hy an increase in the defor-mability of sarcoma cells after enzymic removal of sialic acid residues.424 Enzymic release of sialic acids from the zona pellucida of rabbit ovum lessens the rigidity of this cell, and spermatozoa can no longer penetrate it.425 Glycoproteins on the surface of sea-urchin eggs... 

Glycoproteins solubilized from plasma-cell membranes of murine tumours have been shown to contain sialic acid residues that function as antigenic determinants. Differences have been demonstrated in the cell-surface glycoproteins of sarcoma 180 tumour cells grown in vitro in cell culture or in vivo as an ascites form in mice. ... 

Following the early observation of Klenk and Yamakawa and their associates, the presence of sialic acid residues at the surface of numerous cells was established, either by action of neuraminidase followed by determination of the cell electrophoretic mobility or by determination of the sialic acid released. For example, sialic acid residues were detected at the surface of EMich ascites tumor cells (Wallach and Eylar, 1961 Cook et aL, 1962), hamster kidney fibroblasts transformed by polyoma virus (Forrester et aL, 1964), squamous epithelial cells (Berwick and Coman, 1962), solid and ascites sarcoma cells (Cook et aL, 1963 Wallach and de Perez Esandi, 1964), normal and malignant rat liver cells (Kalant et aL, 1964), cells from human bronchial carcinoma, cells from rat myeloma, HeLa cells, and L-strain mouse fibroblasts (Fuhrmann etaL, 1962). 

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